books.google.de - This book studies representable functors among well-known varieties of algebras. All such functors from associative rings over a fixed ring R to each of the categories of abelian groups, associative rings, Lie rings, and to several others are determined. Results are also obtained on representable functors...http://books.google.de/books/about/Cogroups_and_Co_Rings_in_Categories_of_A.html?hl=de&id=s6NnkQs3JBMC&utm_source=gb-gplus-shareCogroups and Co-Rings in Categories of Associative Rings
